1. Field of the Invention
This invention relates to a drawer-type heating cooker having a drawer-type cooking space (container), such as a microwave oven, and more particularly to decision on the driving direction of its open/close door and an open/close door drive controller based on the decision.
2. Description of the Related Art
Conventionally, as disclosed in Patent Document 1 (JP 3-045820A, page 2, lower left column, line 6 to page 3, upper right column, line 16, and FIG. 1 to FIG. 5) and Patent Document 2 (JP 11-237053A, paragraphs 0029 to 0032, and FIG. 1), there are proposals for a drawer-type heating cooker in which a drawer capable of mounting an object to be heated can be drawn out along with an open/close door from the cooker body, and the aperture of the heating chamber can be closed by the open/close door in the housed state where the drawer is housed in the heating chamber of the cooker body. The drawer-type heating cooker of this type includes a device body (cooker body) having a cooking chamber (heating chamber) for housing an object to be heated, an open/close door for blocking the cooking chamber from outside air, and a bottom plate, or a heating container (drawer) capable of mounting an object to be cooked, interlocked with the open/close door. More specifically, the bottom plate or the heating container is smoothly slid by a sliding mechanism, to which the rotational output of a motor is transmitted through a transmission means such as a rack-and-pinion mechanism, so that the bottom plate or the heating container can be drawn out from the device body or moved in the housing direction. When the bottom plate or the heating container is housed in the device body, the open/close door blocks the cooking chamber from outside air. The heating cooker disclosed in Patent Document 2 includes a heating container that can be drawn out from the cooker body. An aperture is formed on top of the heating container, and is covered with a lid to form a heating chamber for confining microwaves. A choke groove is provided between the aperture periphery and the lid of the heating container to prevent leakage of radio waves.
However, automatic drawer-type opening/closing in conventional drawer-type heating cookers is realized only by automatic opening/closing based on operation of a keypad disposed on the body or the open/close door of the heating cooker. Furthermore, when the open/close door is manipulated by manual opening/closing, the drawer is also moved with the open/close door. However, automatic opening/closing interlocked with manual opening/closing has not been realized.
Patent Document 3 (JP 2005-190546A, paragraphs 0055 to 0063) discloses an audio-visual device such as a video tape recorder or a video disk player in which a tray for holding a recording medium is transported by a transporting apparatus. When a user manually pushes the tray by a certain amount, a detection switch is triggered, and the transporting apparatus draws the tray into the device by a drive motor. A rotational force insufficient for activating the transporting apparatus is applied to the drive motor in advance, and the user's manual operation is immediately assisted by the rotational force of the drive motor to reduce the user's labor. However, the action of assisting the user's manual operation by the transporting apparatus is limited to the action of drawing the tray into the device.
In the heating cooker, the portion moving with opening/closing has significantly large mass than that in the audio-visual device. Hence the drive mechanism in the heating cooker is greatly different in configuration from that in the transporting apparatus of the audio-visual device. Furthermore, the heating cooker needs automatic opening/closing interlocked with manual opening/closing of the open/close door in both directions. Therefore it is extremely difficult to realize automatic opening/closing interlocked with manual opening/closing by applying the transporting apparatus disclosed in Patent Document 3 to a drawer-type heating cooker.
When both hands of a user are occupied with an object to be cooked such as a food item, it is virtually difficult to operate keys provided on the body or the open/close door of the cooker. In such situations, the user tries to close the open/close door with any part of the user's body. However, if the user does not know how to operate the keypad, or if the keypad is faulty, the user is forced to manually open/close the door.
Thus there is a problem to be solved with the automatic open/close door of a drawer-type heating cooker. More specifically, when a user performs manual opening/closing operation, irrespective of the direction of the manual operation of the open/close door, it is desirable to cause a drive means for door opening/closing to start automatic opening/closing of the door in that direction, thereby alleviating the burden of manual opening/closing of the door.